Design of a Benchtop Facility for Parametric Evaluation of Engine Oil Quality
Smith, Adam David
Engine health monitoring is an emerging technology with economic and environmental benefits in automotive, marine, and industrial diesel engines applications. Engine oil quality is a strong marker of engine health and performance. Advances in in situ oil quality sensing offer an end use-based customized approach in determining oil change requirements. The primary cause of engine oil degradation is the oxidation of its constituent hydrocarbons in the high temperature and high pressure environment of the lubricating surfaces, causing an increase in the concentration of polar molecules. State of the art in situ oil quality sensors (OQS), like the one used in the current study, measure the change in an oil’s electrical permittivity (loss factor) as it degrades. To systematically study the performance characteristics of the OQS under controlled conditions of temperature, flow rate, and sensor spatial orientation, a benchtop facility capable of replicating the oil flow characteristics in a testbed diesel engine has been designed, built, and evaluated. This facility is equipped with precision instrumentation to accurately measure and control temperature and flow rate conditions representative of engine startup and operation. Pressure drop studies of the oil filter complex showed that the viscous flow and temperature-dependent variation in filter permeability could be well represented by dimensional analysis techniques. It was observed that the new generation of OQSs are orientation agnostic, and their loss factor response shows a temperature dependence that can be modeled to predict loss factor measurements at engine operating temperatures using both traditional and machine learning methods.